Many types of buildings, such as commercial and government office buildings, utilize suspended ceilings. Suspended ceilings typically include a suspension grid system and acoustical panels. The grid system for example may be used to suspend the panels, otherwise known as tiles, from the overhead building structure generally in a single plane. The suspended ceiling is formed by coupling the grid to hangar wires attached to the building structure, and thus the load of the grid system with its associated lighting components, air distribution components, and acoustical panels is transferred to the building structure by the hanger wires. A variety of types of lay-in ceiling panels are available for use with exposed grids including cast, water-felted, fiber glass, gypsum, and metal.
Grid systems may be formed using main beams or “tees,” cross tees, and hangers. The main beams are metal framing members that are hung from the hangers. The cross tees typically are metal framing members snap-fitted to the main beams, perpendicular thereto.
One popular variant of the suspended ceiling is a suspended ceiling system that utilizes a grid framework formed of inverted T-shaped frame members for the main tees and cross tees. The frame members are configured to form a suspended grid including multiple grid elements, which are known as modules. These modules may be provided in any practicable size, with 24-inch squares being a common module size. The suspended ceiling is formed by installing ceiling tiles in a number of modules such that each edge portion of the bottom surface of each tile is supported by an inverted T cross bar—a main or cross tee. The suspended ceiling system is completed by including required utilities in the system such as fire sprinklers, heating, ventilating and air conditioning (HVAC) elements, and lighting fixtures. Suspended ceiling systems for example may provide decoration, light reflection, and/or masking of utility infrastructure.
In many applications, it is desirable that a suspended ceiling system provide a significant degree of acoustic insulation or damping. In particular, in an office environment where speech privacy is important, it is desirable to limit the amount of sound that can otherwise travel through the ceiling in one office, conference room, or space and be readily received in another office, conference room, or space.
Utilizing ceiling tiles made from sound absorbing material can provide a measure of acoustic insulation in a suspended ceiling system. For example, U.S. Pat. No. 5,832,685 to Hermanson is directed to a self-supporting, sound absorbing interior surface panel as well as a suspended ceiling module comprising a support structure, such as a tee bar grid, and a panel which could be supported within the module in either tegular or coffered orientation.
Using sound absorbing ceiling tiles alone, however, does not provide acoustic insulation at modules of a suspended ceiling system where lighting fixtures are installed. To this end, various devices are known for providing acoustic insulation with respect to lighting fixtures.
For example, U.S. Pat. No. 4,094,379 to Steinberger is directed to a sound-absorption panel. The panel is suspended in horizontal position toward a light and need only be translucent to permit light to pass downwardly and so as hide objects above the ceiling.
U.S. Pat. No. 6,450,289 B1 to Field et al. is directed to a noise attenuation device. A noise attenuator is disclosed for use adjacent to a light fitting for attenuating noise from air conditioning or an air supply to offices. The attenuator can be connected to the duct system above a standard vent slot adjacent a light fitting and connected to an office air conditioning system.
U.S. Pat. No. 6,481,173 B1 to Roy et al. is directed to a fiat panel sound radiator with special edge details. A flat panel radiator is mounted inside a tegular frame with the lower edge of the tegular frame below the flanges of the main beams. The radiator panel call be fabricated from a honeycomb core. A combination of containment elements and isolation elements are used to isolate the radiator panel from the tegular frame both mechanically and acoustically. An acoustic scrim is attached to the bottom of the tegular frame.
Despite these developments, there remains a need for an improved acoustic housing that can be positioned above a lighting fixture installed in a suspended ceiling system. There further remains a need for an acoustic housing such as an acoustic hood that is not supported by ceiling tiles, thereby allowing ceiling tiles to be removed or replaced without being disturbed. Additionally, there remains a need to an acoustic housing that is formed in multiple parts for ease of installation in the constricted confines presented by known suspended ceiling systems. There also remains a need for a recessed light fixture that includes an acoustic component such as at least one soundproofing layer, thereby providing sound absorption where the light fixture is installed as a component of a suspended ceiling system.